User manual STUDIO PROJECTS VTB1

[. . . ] Before you connect anything to your new VTB1, be sure to turn down all of the input and output levels. Be sure to plug the barrel connector into the VTB1 first, and then plug it into an electrical supply outlet. Using a good quality XLR cable, connect your microphone to the VTB1 XLR input on the back of the VTB1. Using either the XLR, or the 1/4" output, hook this into your recorder, computer card, or whatever you are recording or playing into. [. . . ] 2-Stage design for increased performance; transistor stage provides up to 45dB gain, 2nd stage contributes up to 15dB gain. Line Input: FET-input opamp buffer with hi input impedance to avoid pickup loading when used as an instrument preamp. 2nd stage provides adjustable gain from 10dB to 30dB, constant hi-impedance is maintained. Hi-pass filter: 75Hz hi-pass filter for low-freq wind and rumble elimination (3-pole filter @-18dB/oct). Tube Blend: Constant-level blend control allows the user to smoothly change from an all solid-state path to a tube-based preamp. This allows the user to add the desired amount of tube sound to the signal without having to deal with complicated "tube drive" controls and such. Alternately, it allows the user to use only the solid-state portion of the preamp to get a very low distortion, un-colored sound when desired. Tube Stage: 12AX7 vacuum tube with DC filament supply for minimum hum and noise. 1st half of tube is operated as a hi-gain amplifier stage, 2nd half operates as a cathode follower to minimize loading of the first stage. A low-voltage plate supply is used to create a "starved-tube" condition for enhanced sound. Output Stage: Bipolar, lo-noise, hi output-current opamp used for best performance. 1st stage is used to provide additional gain (6dB) and drives the Line out jack and Pin-2 of the balanced out. The 2nd stage provides signal inversion and drive for Pin-3 of the balanced output (effectively an additional 6dB gain). For best Tube-Sound results: The tube operates best when provided with a solid signal. The best way to accomplish this is to use the on-board metering to set the internal levels. Press the Meter Select switch IN, the meter will now display the signal level within the preamp, just before the tube stage. Adjust the GAIN control to get a meter reading within the 0 to +8 range. With the OUTPUT control at "0", start turning the BLEND control clockwise until the desired sound is heard. Depending on the source material, more or less BLEND will be needed. If the output level is too high or low for your following equipment, adjust the OUTPUT control to compensate. This won't change the sound of the blended signal, just the overall level. 5 6 PROBLEMS Studio Projects electronics are extremely resistant to physical damage, but if the unit fails to work after being dropped, it should be returned in adequate packing to the supplier. A double test and inspection system means that manufacturing faults are non-existent but should any fault occur, it will be repaired (or replaced) free of charge except where the fault has been caused by physical damage. (SEE WARRANTY INFORMATION) TROUBLESHOOTING 1) The microphone doesn't work! [. . . ] B: In addition, PMI Audio Group will supply, at no charge, replacements for defective parts for a period of (one year) from the date of purchase. During the labor warranty period, to repair the Product, Purchaser must return the defective Product, freight prepaid, or deliver it to PMI Audio Group Service Center. The product to be repaired is to be returned in either its original carton or a similar package affording an equal degree of production. PMI Audio Group will return the repaired Product freight prepaid to the Purchaser. [. . . ]